Vaporizing apparatus for liquids

ABSTRACT

An apparatus is disclosed for delivering a controlled and metered amount of vapors of a vaporizable liquid in a carrier gas to a destination for use there (e.g., ether vapors to a mask for use in anesthesia during surgery). A feature of the apparatus is a metering device in which the height of a ball floating in the gas stream indicates the rate of flow.

This invention relates to a vaporizing apparatus for liquids whichpreferably evaporate at room temperature. Prior art vaporizingapparatuses used in medicine, for instance for dosing liquid anestheticsuch as ether to a patient, have drawbacks in that the amount ofvaporized ether cannot be directly measured and thus not visuallycontrolled during the procedure.

The aim of this invention is to eliminate the said drawbacks by means ofan apparatus in which the total gas flow is led to a three-way valvefrom where one way leads one part of the gas to an ejector which causessuction downstream of a metering device and the other part of the gasflows to another three-way valve which divides the gas further into twoparts of desired proportion, so that one part flows directly to themetering device, and the other part flows through a vaporizing vessel tothe metering device. The metering device is calibrated so that itindicates a desired gas flow already in zero position. Thus the gas flowpassing through the vaporizing vessel is saturated by vapour whichcauses an increase in the indication of the metering device and thisincrease represents the proportion of the vapour in the total flow.

The above aims are achieved by an apparatus according to the invention,the characteristics of which are set forth in the claims.

Preferred embodiments of the invention will now be described withreference to the accompanying drawings in which:

FIG. 1 shows schematically one embodiment of a vaporizing apparatusaccording to the invention,

FIG. 2 shows schematically another embodiment of a vaporizing apparatusaccording to the invention,

FIG. 3 shows a front view of a flow meter belonging to a vaporizingapparatus according to the invention,

FIG. 4 shows a section of the flow meter of FIG. 3, taken on line I--I,and

FIG. 5 shows an enlargened top view of the flow meter of FIG. 3, insection taken on line II--II of FIG. 3.

The capital letters refer to gas flows.

As shown in FIG. 1, the total gas flow A is led to a three-way valve 3a,where it is divided into two parts, B and C. Part C is led to athree-way valve 3b, which has an initial position where C = E; thissituation represents the zero position of a metering device 2. Whenvapour is needed, flow D is adjusted by the valve 3b so that a desiredamount of vapour is carried by the gas flow. The greatest amount ofvapour is carried when C = D, E = O and F + vapour = H. The position ofa ball 2a of the metering device indicates the proportion of vapour inthe gas flow. The construction of the metering device 2 is such that theball in it already in zero position represents a certain gas flow. Thepurpose of an ejector 13, where gas flow B is led to, is to assist invaporizing the liquid by causing underpressure downstream of themetering device 2.

In FIG. 2, a controlling meter 4 is arranged in the vaporizing apparatusbefore the three-way valve 3b, in order to measure gas flow C. Onefeature of the invention is the changeability of the scales of the twoflow meters so that the vaporizing apparatus can be used for vaporizingseveral different liquids, i.e. the use of the apparatus is notrestricted to vaporizing only a certain liquid. According to theinvention, it is preferable to use also a throttle 5 in the gas flowafter the second flow meter 2. In this way the meter is steady andeasier to read.

As shown in FIG. 2, the total gas flow A is led to the three-way valve3a where it is divided into two parts: gas flow B and gas flow C.According to the invention, gas flow C is led through the meteringdevice 4 to the three-way valve 3b. The metering device 4 may be similarto the metering device 2. The controlling flow meter 4 is preferablymade so that it is at least partly transparent. The ball 4a of themetering device 4 indicates the rate of gas flow C. In the three-wayvalve 3b gas flow C is divided into flows E and D in desired proportion.Gas flow E is led directly to the metering device 2 and gas flow D isled to the metering device 2 through the vaporizing vessel 1. Flow Fcoming from the vaporizing vessel 1 to the metering device 2 includes,besides gas flow D, also vapour from the vaporizing vessel 1. Gas flow Hafter the metering device 2 is throttled at point 5 in a suitable way sothat the positions of the balls 2a and 4a of the metering devices are assteady as possible. In this way the metering devices 2 and 4 are easierto read.

The metering devices 2 and 4 are preferably provided with changeablescales, each liquid to be vaporized having its own scale. In this waythe use of the vaporizing apparatus is not restricted only to vaporizingone certain liquid, and it can be used for vaporizing several variousliquids while it is always possible to observe the proportion of eachvapour in the total gas flow.

A flow meter 2, 4 belonging to an apparatus according to the inventionwill be described in the following, with reference to FIGS. 3 to 5.

The flow meter in question can be used for measuring gas and liquidflows in a whole desired range of flow variations or only in a part ofthe range, i.e. above a certain flow value.

The flow meter comprises two tubes 6 and 7, the tube 7 being within thetube 6. The outer tube 6 is made of transparent material, preferablyglass or plastic. The material of the inner tube 7 is metal, glass orplastic, for instance. According to the invention, the inner tube 7 hasa longitudinal groove or slot 8, going through the wall of the tube 7and widening upwards when the meter is in operating position. The sidesof the slot 8 are preferably machined straight so that the groove orslot 8 widens evenly from bottom to the top. According to the invention,the tube 7 can be provided also with several grooves or slots 8, forinstance with two slots 8, on opposite sides of the tube 7 so that onecan see through the meter.

A ball 9 is arranged inside the tube 7 of the meter so that the ball canmove freely in the longitudinal direction of the tube 7. The path ofmovement of the ball 9 is restricted at its ends by suitable stoppers 10and 11, made of tube, for instance, so that the length of the path issubstantially equal to the length of the groove or slot 8. It should benoted that the inner diameter of the inner tube 7 is the same along theentire length of the tube differently from prior art meterconstructions.

When a gas or liquid flow is led through a flow meter according to theinvention, the flow meter is in vertical position, as shown in FIGS. 3and 4, so that the wider end of the groove or slot 8 is pointingupwards. A gas or liquid flow passing from below upwards in the tube 7passes in the way shown by arrows 12 in FIG. 4, i.e. it passes the ball9 along the slot 8 or alternatively several slots 8. If the gas orliquid flow increases, it pushes the ball 9 upwards in the tube 7 sothat the transverse area of the slot or slots 8 at the position of theball 9 corresponds to the flow. If the gas or liquid flow decreases, theball 9 sinks correspondingly in the tube 7. Thus the position of theball 9 indicates the rate of flow through the meter. The meter isprovided with a scale at a suitable location, for instance on thesurface of the inner tube 7, on the sides of the slot 8, so that therate of flow can be read directly on the scale from the position of theball 9.

The accuracy of the flow meter depends on the thickness of the wall ofthe inner tube 7 and on the increase in width per length of the slot,among other things. By means of the above variables it is possible todefine what length of the scale, i.e. what movement of the ball 9corresponds to a certain volume flow through the meter. Thus a scale ofdesired length and also of required accuracy can be made for instancefor volume flow variations from 0 to 2 liters per minute.

The flow meter can also be made so that it shows the rate of flow onlystarting from a certain value of the rate of flow. In this case the ball9 of the flow meter stays in its lower position on flow rates smallerthan the flow rate in question, because the lower end of the slot 8 hasbeen made to correspond to the flow rate in question. The gas or liquidflow can pass the ball 9 in its lower position freely through the slot 8until the flow increases to a certain value. Only when the rate of thevolume flow further increases after this, the ball 9 rises in the tube 7and indicates the rate of volume flow passing through the meter. Themovement of the ball 9 in the meter is even, at least when only one slot8 is used, because the ball 9 then rolls evenly in the tube 7 along thewall opposite to the slot 8. But even with several slots 8, the ball 9cannot move unevenly to any noticeable degree because the inner diameterof the tube 7 is the same along the entire length of the tube 7 and thediameter of the ball 9 can be chosen to be nearly the same as the innerdiameter of the tube 7. The invention is not, of course, limited to theabove embodiments, and it can vary considerably in details within thescope of the claims.

We claim:
 1. Apparatus for delivering controlled and metered amounts ofvapors of volatile liquids to a point of utilization, said apparatuscomprising:a. a source of carrier gas, gas-flow metering means, and areservoir for volatile liquid; b. adjustable valve means connected tosaid flow metering means and to said reservoir for dividing a gas streamfrom said source of carrier gas into a first fraction flowing directlyto said flow metering means and into a second fraction flowing to saidreservoir; c. separate gas conducting means connecting said valve withsaid flow metering means and with said reservoir; d. gas conductingmeans connecting said reservoir directly to said flow metering means;and e. suction means connected to said flow metering means downstreamthereof for inducing flow of gases and assisting evaporation of volatileliquid from said reservoir.
 2. Apparatus for delivering controlled andmetered amounts of vapors of volatile liquids to a point of utilization,said apparatus comprising:a. a source of carrier gas, first and secondgas-flow metering means, and a reservoir for volatile liquid; b. a firstthree-way valve connected to said source of carrier gas for dividing astream of gas from said source into first and second portions; c.ejector means and means for connecting said ejector to said firstthree-way valve for conducting said first portion of gas stream to saidejector means; d. means for connecting said first three-way valve to theinlet end of said first gas-flow metering means for conducting thesecond portion of the carrier gas to said first gas-flow metering means;e. a second three-way valve and means connecting the inlet of saidsecond three-way valve with the outlet of said first gas-flow meteringmeans for conducting the metered second portion of said carrier gas tosaid second three-way valve; f. means for connecting one exit port ofsaid second three-way valve to said reservoir; g. means for connecting asecond exit port of said second three-way valve to the inlet end of saidsecond gas-flow metering means; h. means for connecting said reservoirto the inlet end of said second gas-flow metering means; and i. meansfor connecting the outlet end of said second gas-flow metering means tosaid ejector means.
 3. The apparatus of claim 2 wherein a throttle valveis inserted between the outlet end of said second gas-flow meteringmeans and said ejector.
 4. Apparatus according to claim 2 wherein theflow meter comprises a tubular body and a floatable ball inside saidtubular body freely movable therein in the axial direction thereof toindicate the rate of gas or liquid flow, said tubular body comprising anouter tube and a coaxial inner tube, said outer tube being oftransparent material, said inner tube having at least one longitudinalslot extending through the wall thereof, the sides of said slotdiverging vertically upward in the direction of gas or liquid flow whensaid flow meter is in its operating position, whereby liquid or gasflowing in an upward direction passes around said ball and through saidlongitudinal slot causing said ball to rise and float in a position inaccordance with the rate of flow of liquid or gas through said flowmeter.
 5. Apparatus for delivering controlled and metered amounts ofvapors of volatile liquids to a point of utilization, said apparatuscomprising:a. a source of carrier gas, gas-flow metering means, and areservoir for volatile liquid; b. a first three-way valve connected tosaid source of carrier gas for dividing a stream of gas therefrom intofirst and second portions; c. suction means connected to said firstthree-way valve for receiving said first portion of carrier gas; d. asecond three-way valve connected to said first three-way valve forreceiving said second portion of the stream of carrier gas to subdividesaid second portion into third and fourth portions; e. means connectingsaid second three-way valve with the inlet end of said flow meteringmeans for conducting said third portion of carrier gas to said flowmetering means; f. a reservoir for vaporizable liquid and meansconnecting said second three-way valve with said reservoir forconducting the fourth portion of said carrier gas to said reservoir; g.means connecting said reservoir directly to the input end of saidgas-flow metering means for conducting mixed carrier gas and vapors tosaid gas-flow metering means; and h. means connecting the output end ofsaid gas-flow metering means to said suction means to mix the stream ofvapor-containing carrier gas with said aforementioned first portion ofcarrier gas.
 6. Apparatus according to claim 5 wherein the flow metercomprises a tubular body and a floatable ball inside said tubular bodyfreely movable therein in the axial direction thereof to indicate therate of gas or liquid flow, said tubular body comprising an outer tubeand a coaxial inner tube, said outer tube being of transparent material,said inner tube having at least one longitudinal slot extending throughthe wall thereof, the sides of said slot diverging vertically upward inthe direction of gas or liquid flow when said flow meter is in itsoperating position, whereby liquid or gas flowing in an upward directionpasses around said ball and through said longitudinal slot causing saidball to rise and float in a position in accordance with the rate of flowof liquid or gas through said flow meter.